setLeft($left) ->setRight($right); } private function setLeft($left): ExceptionNotEquals { $this->left = $left; return $this; } private function setRight($right): ExceptionNotEquals { $this->right = $right; return $this; } /** * @return array|string */ public function getLeft() { return $this->left; } /** * @return array|string */ public function getRight() { return $this->right; } }